Dovetailietg-machine



T OFFTCE.

JNO. BELL, OF HARLEM, NEV YORK.

DOVET'AILING-MAOHINE.

Specification of Letters Patent No.

To all whom it may concern:

Be it known that I, JOHN BELL, of Harlem, in the county and State of New York, have invented certain new and useful Improvements in Machines for Cutting Dovetails or Double-Inclined Tenons; and I do hereby declare the following to be a full., clear, and exact description of the same, reference being had to the accompanying drawings, making a partv thereof, in which- Figure l, represents a perspective view of the entire machine; Fig. 2, a vertical cross section, with the clamp or box for holding the pieces in place; Fig. 3, a longitudinal vertical section through the line a, b, of Fig. 2. Fig. 4 represents a perspective view of the clamp or box and the pieces in it, de tached. Fig. 5, represents the manner in which the tenons and dovetails are put together.

The nature of this invention relates to the use of a series of rotating chisels, saws, or other cutting implements, with a suitable table and clamp so that by their united action a series or nest of boards can be dovetailed by one operation so as to be completely finished and ready to be joined together for boxes or similar articles. The chisels A, by means of which, said dovetails, or double inclined tenons are cut, are placed and firmly secured into a horizontal shaft B, and said shaft or its boss or cutter stock may have a tapering shape from the middle toward its end, as represented in the drawings. The journals of said shaft B, play in bearings, which are fixed in the frame C, and thus when the shaft B, is turned, the edges of the chisels or saws A, will make a circular motion around the shaft; the shape of the chisels A when chisels are used, is shown in Fig. 3.

As represented in Fig. 2, the length of each subsequent dchisel is diminished in such a degree, that a straight line drawn through the edge of each chisel will be parallel to the inclined plane or tables D, on which the edge of the boards rests, into which the dovetails, or onto which the double inclined tenons are to be cut. There are two of these inclined table or planes D, each corresponding to a set of chisels as represented in Figs. l and 2, and each is provided with a square opening of suiiicient size to let the edges of the chisels project through, both being in such a manner that the length of that part 13,696, dated. October 23, 1855.

of the chisel which overreaches the inclined plane at its highest position is equal to the depth of the tongues or grooves to be cut. Each of the inclined tables or planes are provided with two tongues 7L, L, running parallel and through the whole length of said tables. If a rectangular shaped board is set edgewise onto the inclined plane, in, a position perpendicular to said plane, the cutters A when set in motion will cut grooves into it which are oblique to any of the sides of said rectangular shaped board, and as the chisels are set into the shaft in such a manner that each space between two chisels has exactly the same width as the edge of chisel itself, it will give to the tongues and grooves the same form in reverse. By this arrangement any two boards dovetailed in this manner by the same set of chisels may be joined exactly together to a right angle as represented in Fig. 5, where m and n represent two such boards, and o, the bottom piece nailed to the sides.

To enable the operator to dovetail a number of boards at one operation, said boards are set in an upright position into a box E, represented in Figs. 2 and 4L, in which box they can be kept in a fixed position, by screwing down the set screws el; the shape of this box must be an oblique parallelogram for the following reasons, viz. The boards r, when set into said box are set parallel to the sides f, the set screws d are then screwed down, and keep the boards 7, in a fixed position; the box E is then set on to the inclined plane D, in such a manner that the tongues h, 7L, will t into the grooves g, g, and t-hus the box F can slide on the plane D in a direction which is parallel to the grooves g, l(7. When the cutting chisels are set in motion they strike the edges of the boards in a direction which is oblique to their sides, and thus the grooves and tongues cut into said boards are oblique in two different directions, and through all the corresponding sides of the tongues are parallel to each other, and thus form a parallelopiped, still none of its angles are right angles, but all oblique ones. The lobject of this is that when two boards m and n, are fitted together by dovetails as described it will be impossible t0 separate them in any horizontal or vertical direction; they can only be separated in a direction parallel to the lines p, and this separation is prevented by nailing a bottom piece 0, to the sides m and n, after which they cannot be drawn apart without breaking them.

It is obvious that the depth of each groove, and the height of each tongue, must be equal to the thickness of the boards to form a finished surface when fitted together ;4

for that purpose it is necessary that the distances of the inclined planes D from the center of the shaft B, can be regulated so as to dovetail boards of different sizes; this may be accomplished by the following arrangement. The inclined planes D are, at both their ends, secured onto cross pieces P, which rest on the frame C; one of these cross pieces P is fixed to the frame C, and it can be raised or lowered thereon by means of the screws S, which play in nuts on the frame C, and thus by raising or lowering said inclined planes, the grooves and tongues will be cut respectively deeper or shallower, which affords the means to dovetail thin and thick boards on the same machine.

The bed or table may be made of slats or ribs so as to allow the chips or shavings to drop through and clean itself, and other obvious changes may be made without departing from the general principle of the machine, which is to out dovetails or double oblique tenons in nests of pieces held in a clamp, so that said pieces can be readily united to form boxes or other similar things, without other fastenings than nailing on the bottom of the box or other thing.

Having thus fully described the nature of my invention, what I claim therein as new and desire to secure by Letters Patent isl. The combination of the boX, clamp, or

frame E, or its eopu'ivalentYV for holding the 

